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Retinoic acid signaling is essential for formation of the heart tube in Xenopus.
- Source :
-
Developmental biology [Dev Biol] 2006 Mar 01; Vol. 291 (1), pp. 96-109. Date of Electronic Publication: 2006 Jan 19. - Publication Year :
- 2006
-
Abstract
- Retinoic acid is clearly important for the development of the heart. In this paper, we provide evidence that retinoic acid is essential for multiple aspects of cardiogenesis in Xenopus by examining embryos that have been exposed to retinoic acid receptor antagonists. Early in cardiogenesis, retinoic acid alters the expression of key genes in the lateral plate mesoderm including Nkx2.5 and HAND1, indicating that early patterning of the lateral plate mesoderm is, in part, controlled by retinoic acid. We found that, in Xenopus, the transition of the heart from a sheet of cells to a tube required retinoic acid signaling. The requirement for retinoic acid signaling was determined to take place during a narrow window of time between embryonic stages 14 and 18, well before heart tube closure. At the highest doses used, the lateral fields of myocardium fail to fuse, intermediate doses lead to a fusion of the two sides but failure to form a tube, and embryos exposed to lower concentrations of antagonist form a heart tube that failed to complete all the landmark changes that characterize looping. The myocardial phenotypes observed when exposed to the retinoic acid antagonist resemble the myocardium from earlier stages of cardiogenesis, although precocious expression of cardiac differentiation markers was not seen. The morphology of individual cells within the myocardium appeared immature, closely resembling the shape and size of cells at earlier stages of development. However, the failures in morphogenesis are not merely a slowing of development because, even when allowed to develop through stage 40, the heart tubes did not close when embryos were exposed to high levels of antagonist. Indeed, some aspects of left-right asymmetry also remained even in hearts that never formed a tube. These results demonstrate that components of the retinoic acid signaling pathway are necessary for the progression of cardiac morphogenesis in Xenopus.
- Subjects :
- Animals
Body Patterning
Embryo, Nonmammalian metabolism
Female
GATA4 Transcription Factor biosynthesis
Gene Expression Regulation, Developmental
Homeobox Protein Nkx-2.5
Homeodomain Proteins biosynthesis
Mesoderm physiology
Myocardium metabolism
Signal Transduction
Transcription Factors biosynthesis
Tretinoin antagonists & inhibitors
Xenopus Proteins biosynthesis
Xenopus laevis
GATA4 Transcription Factor physiology
Heart embryology
Homeodomain Proteins physiology
Transcription Factors physiology
Tretinoin physiology
Xenopus Proteins physiology
Subjects
Details
- Language :
- English
- ISSN :
- 0012-1606
- Volume :
- 291
- Issue :
- 1
- Database :
- MEDLINE
- Journal :
- Developmental biology
- Publication Type :
- Academic Journal
- Accession number :
- 16423341
- Full Text :
- https://doi.org/10.1016/j.ydbio.2005.12.018